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CALIPER paediatric reference intervals for the urea creatinine ratio in healthy children & adolescents
Mary Kathryn Bohn1, Victoria Higgins1, Khosrow Adeli1
1CALIPER Program, Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, ON, Canada; Department of Laboratory Medicine & Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
Insights
Establishing age- and sex-specific reference intervals (RIs) for the urea creatinine ratio (UCR) in children is crucial. New continuous and discrete RIs were determined, accounting for assay methods to improve pediatric test interpretation.
Area of Science:
- Clinical Chemistry
- Pediatric Laboratory Medicine
- Biomarker Reference Intervals
Background:
- The urea creatinine ratio (UCR) is clinically significant for diagnosing conditions like acute kidney injury.
- Established pediatric reference intervals (RIs) for UCR are lacking, hindering accurate interpretation.
- This study addresses the need for robust UCR RIs in healthy children and adolescents.
Purpose of the Study:
- To determine age- and sex-specific discrete and continuous reference intervals (RIs) for the urea creatinine ratio (UCR).
- To establish normative UCR values in a pediatric cohort.
- To improve the interpretation of UCR test results in children.
Main Methods:
- UCR was calculated from urea and creatinine data in approximately 1030 children from the CALIPER cohort.
- Discrete RIs were established using Clinical and Laboratory Standards Institute (CLSI) guidelines.
- Continuous RIs were determined using nonparametric quantile regression, with partitions identified via the Harris & Boyd method.
Main Results:
- Age- and sex-specific partitions were necessary to reflect physiological changes in UCR during childhood and adolescence.
- Significant differences in UCR RIs were observed between Jaffe and enzymatic creatinine assay methods.
- Continuous RI establishment proved beneficial for capturing dynamic trends.
Conclusions:
- Stratification of UCR RIs by age, sex, and creatinine assay methodology is critical for accurate pediatric interpretation.
- These findings provide essential data for understanding normative UCR values in pediatric populations.
- The established RIs are expected to enhance the clinical utility of UCR testing in children.
Background:
The urea creatinine ratio (UCR) is important in the clinical assessment of several medical conditions, including acute kidney injury and gastrointestinal bleeding. However, accurate and robust paediatric reference intervals (RIs) for this ratio have not been well established. Here, we determined age- and sex-specific discrete and continuous RIs for UCR in the Canadian Laboratory Initiative on Paediatric Reference Intervals (CALIPER) cohort of healthy children and adolescents for the first time.
Methods:
UCR was calculated for approximately 1030 CALIPER participants using retrospective urea and creatinine (both Jaffe and enzymatic methods) normative data. Partitions were determined using the Harris & Boyd statistical method. Discrete RIs were established in accordance with the Clinical and Laboratory Standards Institute (CLSI) guidelines. Continuous RIs were established using nonparametric quantile regression.
Results:
Several age- and sex-specific partitions were necessary to capture dynamic physiological trends associated with this ratio throughout childhood and adolescence, highlighting the benefit of continuous RI establishment. Established UCR RIs also demonstrated marked differences between Jaffe and enzymatic assay methods.
Conclusion:
Our results clearly demonstrate the critical need for RI stratification by important covariates such as age, sex, and creatinine assay methodology for paediatric UCR test result interpretation. These data contribute to our understanding of normative UCR values in childhood and adolescence and can be expected to improve paediatric test result interpretation in clinical laboratories that report this ratio.
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